1. Technical Field
The present invention relates to light-stable compositions useful for rendering polyamide fiber-containing textile articles resistant to staining by acid dyes that are found, for example, in foods and beverages; processes for forming such compositions; polyamide fiber-containing textile articles whose fibers have been so rendered; and processes for imparting stain resistance to such textile articles.
As used herein, the word "polyamide" in "polyamide fiber" means fiber or sheet-formable polymers of organic bifunctional amino-, hydroxy-, carbonyl-, amino-hydroxy-, and carboxyl compounds and which contain linkages of the general formula: ##STR1## where R can be H, unbranched or branched, unsubstituted or substituted C.sub.1 -C.sub.12 alkyl, cycloalkyl, alicyclic, aromatic or other groups, and n is an integer greater than one. Included among such polyamides are synthetic polyamides, e.g., nylons, and polypeptides such as constitute protein fibers, e.g., wool and silk. The term "fiber" includes fibers of continuous or indefinite length (i.e., filaments) and fibers of relatively short length (e.g., staple).
The term "stain resistance" as used herein with reference to textile articles means the ability to resist staining by Kool-Aid according to the Stain Resistance Test described below. The purpose of the test is to identify textile articles having durable and lasting resistance to staining normally caused by acid dyes such as are found in various foods and beverages.
The term "lightfastness" as used herein with reference to textile articles means the ability to resist yellowing when subjected to radiation from a xenon light source that approximates intense sunlight under the Lightfastness Test given below. The purpose of the test is to identify textile articles having improved light-fastness to yellowing normally caused by prolonged exposure to sunlight.
2. Description of Background Art
Compositions used in the textile field to impart resistance to staining, for example, by acid dyes found in foods and beverages, have important applications to textile articles including those made of polyamide fibers, e.g., nylon, wool and silk. Several formulations that have been sold and used for this purpose are available, such as Mesitol NBS from Mobay Chemical Company, Product FX 366M from 3M and Product 311A from E. I. du pont de Nemours and Company.
However, a common problem with these previously known products is their lack of stability towards light, particularly in the ultraviolet region of the spectrum. This characteristic causes textile articles treated with these products to turn yellow and become discolored upon prolonged exposure to sunlight. The discoloration is believed to be the result of the decomposition of the aromatic moieties of the composition where the methylene group is attached to the ring structure. The problem of such discoloration usually is compounded by the concomitant loss of stain resistance.
Accordingly, it is an object of the present invention to provide a light-stabile composition for providing polyamide (e.g., nylon, wool and silk) fiber-containing textile articles with improved resistance to staining by acid dyes found in food beverages and other products. The invention is also intended to provide processes for making the aforementioned light stabile compositions. Another object is to provide textile articles whose fibers have been rendered stain resistant by contacting the fibers with the aforementioned light stabile compositions. Yet another object is to provide processes for preparing the aforementioned stain resistant textile articles.
These and other objects of the invention, as well as a fuller understanding of the advantages thereof, can be had by reference to the following description and claims.